Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Acura >> 2011 >> TL Base >> Repair and Diagnosis >> Engine Mechanical >> Auxiliary Emission Control Systems >> EGR System >> DTC Troubleshooting >> DTC P0401: EGR Insufficient Flow

DTC P0401: EGR Insufficient Flow

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION )
  1. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
  2. Clear the DTC with the HDS
  3. Start the engine Hold the engine speed at 3,000 rpm without load (A/T in P or N, M/T in neutral) until the radiator fan comes on, then let it idle
  4. Do the EGR TEST in the INSPECTION MENU with the HDS

    Is the result OK? 

    YES  -Go to step 5

    NO  -Go to step  7

  5. Test-drive under these conditions
    • Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C)
    • A/T in D, M/T in 4th
    • Drive at a steady speed between 55-75 mph (88-120 km/h) for at least 10 seconds
    • During the drive, decelerate (with the throttle fully closed) for 5 seconds
  6. Monitor the OBD STATUS for DTC P0401 in the DTCs MENU with the HDS

    Does the screen indicate FAILED? 

    YES  -Clean the intake manifold EGR port and EGR pipe (see EGR VALVE REPLACEMENT ) with throttle plate cleaner Also, clean the passage inside the EGR valve with throttle plate cleaner, then go to step  9

    NO  -If the screen indicates PASSED, intermittent failure, the system is OK at this time Check for poor connections or loose terminals at the EGR valve and the PCM If the screen indicates EXECUTING, keep driving until a result comes on If the screen indicates OUT OF CONDITION, go to step  5 and recheck.

  7. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
  8. Replace the EGR valve (see EGR VALVE REPLACEMENT )
  9. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
  10. Reset the PCM with the HDS
  11. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE )
  12. Test-drive under these conditions
    • Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C)
    • A/T in D, M/T in 4th
    • Drive at a steady speed between 55-75 mph (88-120 km/h) for at least 10 seconds
    • During the drive, decelerate (with the throttle fully closed) for 5 seconds
  13. Check for Pending or Confirmed DTCs with the HDS

    Is DTC P0401 indicated? 

    YES  -Check for poor connections or loose terminals at the EGR valve and the PCM If the connections are OK, go to step  15

    NO  -Go to step 14

  14. Monitor the OBD STATUS for DTC P0401 in the DTCs MENU with the HDS

    Does the screen indicate PASSED? 

    YES  -Troubleshooting is complete If any other Pending or Confirmed DTCs were indicated in step 13, go to the indicated DTC's troubleshooting

    NO  -If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the PCM, then go to step  1 If the screen indicates EXECUTING, keep driving until a result comes on If the screen indicates OUT OF CONDITION, go to step  12

  15. Update the PCM if it does not have the latest software (see ECM/PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE ECM/PCM )
  16. Test-drive under these conditions
    • Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C)
    • A/T in D, M/T in 4th
    • Drive at a steady speed between 55-75 mph (88-120 km/h) for at least 10 seconds
    • During the drive, decelerate (with the throttle fully closed) for 5 seconds
  17. Check for Pending or Confirmed DTCs with the HDS

    Is DTC P0401 indicated? 

    YES  -Check for poor connections or loose terminals at the EGR valve and the PCM If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE ECM/PCM ), then go to step  16 If the PCM was substituted, go to step  1

    NO  -Go to step 18

  18. Monitor the OBD STATUS for DTC P0401 m the DTCs MENU with the HDS

    Does the screen indicate PASSED? 

    YES  -If the PCM was updated, troubleshooting is complete If the PCM was substituted, replace the original PCM (see ECM/PCM REPLACEMENT ) If any other Pending or Confirmed DTCs were indicated in step 17, go to the indicated DTC's troubleshooting

    NO  -If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the PCM If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE ECM/PCM ), then go to step  16 If the PCM was substituted, go to step  1 If the screen indicates EXECUTING, keep driving until a result comes on If the screen indicates OUT OF CONDITION, go to step  16

scientia non olet · About Mike's Workshop Manuals